Latitudinal gradient in species diversity provides high niche opportunities for a range-expanding phytophagous insect.

When species undergo poleward range expansions in response to anthropogenic change, they likely encounter less diverse communities in new locations. If low diversity communities provide weak biotic interactions, such as reduced competition or predation, range-expanding species may experience high niche opportunities. Here, we investigated if oak gall wasp communities follow a latitudinal diversity gradient (LDG) and if lower diversity communities provide weaker interactions at the poles for a range-expanding community member, Neuroterus saltatorius. We performed systematic surveys of gall wasps on a dominant oak, Quercus garryana, throughout most of its range, from northern California to Vancouver Island, British Columbia. On 540 trees at 18 sites, we identified 23 oak gall wasp morphotypes in three guilds (leaf detachable, leaf integral, and stem galls). We performed regressions between oak gall wasp diversity, latitude, and other abiotic (e.g. temperature) and habitat (e.g. oak patch size) factors to reveal if gall wasp communities followed an LDG. To uncover patterns in local interactions, we first performed partial correlations of gall wasp morphotype occurrences on trees within regions). We then performed regressions between abundances of co-occurring gall wasps on trees to reveal if interactions are putatively competitive or antagonistic. Q. garryana-gall wasp communities followed an LDG, with lower diversity at higher latitudes, particularly with a loss of detachable leaf gall morphotypes. Detachable leaf gall wasps, including the range-expanding species, co-occurred most on trees, with weak co-occurrences on trees in the northern expanded region. Abundances of N. saltatorius and detachable and integral leaf galls co-occurring on trees were negatively related, suggesting antagonistic interactions. Overall, we found that LDGs create communities with weaker associations at the poles that might facilitate ecological release in a range-expanding community member. Given the ubiquity of LDGs in nature, poleward range-expanding species are likely moving into low diversity communities. Yet, understanding if latitudinal diversity pattern provides weak biotic interactions for range-expanding species is not well explored. Our large-scale study documenting diversity in a related community of phytophagous insects that co-occur on a host plant reveals that LDGs create high niche opportunities for a range-expanding community member. Biogeographical patterns in diversity and species interactions are likely important mechanisms contributing to altered biotic interactions under range-expansions.

Cuando las especies se expanden hacia los polos en respuesta al cambio antropogénico, es probable que las encuentren comunidades menos diversas en sus nuevos lugares. Si las comunidades de baja diversidad proporcionan interacciones bióticas débiles, como competencia reducida o depredación, las especies que se expanden pueden tener 'oportunidades de alto nicho'. Aquí, investigamos si las comunidades de avispas de las agallas muestran un gradiente de diversidad latitudinal (LDG) y si las comunidades de menor diversidad proporcionan interacciones antagónicas más débiles en los polos para las comunidades que se expanden. Específicamente, investigamos estas relaciones en la comunidad de Neuroterus saltatorius. Realizamos estudios sistemáticos de las avispas de las agallas en un roble dominante, Quercus garryana en la mayor parte de su área de distribución, desde el norte de California hasta la isla de Vancouver, en la Columbia Británica. Sobre 540 árboles en 18 sitios y 6 regiones, nos identificamos 23 mofotipos de avispas de las agallas en tres gremios (hoja desmontable, hoja integral y agallas del tallo). Ejecutamos regresiones entre la diversidad de avispas de las agallas, la latitud, y otros factores abióticos (p. ej., temperatura) y de hábitat (p. ej., tamaño del parche de roble) para revelar si las comunidades de avispas de las agallas siguieron un LDG. Para descubrir tendencias en las interacciones locales, primero ejecutamos correlaciones parciales de ocurrencias de morfotipos de avispas de las agallas en árboles dentro de las regiones. Luego ejecutamos regresiones entre las coocurrencias de las abundancias deavispas de las agallas en los árboles para revelar si las interacciones son supuestamente competitivas o antagónicas. Las comunidades de avispas Q. garryana-gall, siguieron un LDG, con menor diversidad en latitudes más altas, particularmente con una pérdida de morfotipos de agallas de hoja desmontable. Las avispas de las agallas de las hojas desprendibles, incluidas a las especies que se expanden su hábitat, se encontraron en sobre todos los árboles, con coocurrencias débiles en los árboles de la región expandida del norte. Las coocurrencias de las las abundancias de N. saltatorius,las agallas foliares desmontables, e agallas integrales en los árboles se relacionaron negativamente, lo que sugiere interacciones antagónicas. En general, encontramos que los LDG crean comunidades con asociaciones más débiles en los polos que podrían facilitar la liberación ecológica en un miembro de la comunidad que se expanden. Debido de la ubicuidad de los LDG en la naturaleza, es probable que las especies que se expanden hacia los polos se estén trasladando a comunidades de baja diversidad. Sin embargo, no se explora bien la comprensión de si las tendenciasde diversidad latitudinal proporcionan interacciones bióticas débiles para las especies que se expanden. Nuestro estudio degran escala documenta la diversidad en una comunidad relacionada de insectos fitófagos que coexisten en una planta hospedante. Como resultado, revela que los LDG pueden crear oportunidades de grandes nichos para un miembro de la comunidad que se expande. Los patrones biogeográficos en la diversidad y las interacciones entre especies son probablemente mecanismos importantes que contribuyen a las interacciones bióticas alteradas bajo la expansión del hábitat.

The Arthropod Associates of 155 North American Cynipid Oak Galls.

The identities of most arthropod associates of cynipid-induced oak galls in the western Palearctic are generally known. However, a comprehensive accounting of associates has been performed for only a small number of the galls induced by the estimated 700 species of cynipid gall wasps in the Nearctic. This gap in knowledge stymies many potential studies of diversity, coevolution, and community ecology, for which oak gall systems are otherwise ideal models. We report rearing records of insects and other arthropods from more than 527,306 individual galls representing 201 different oak gall types collected from 32 oak tree species in North America. Of the 201 gall types collected, 155 produced one or more arthropods. A total of 151,075 arthropods were found in association with these 155 gall types, and of these 61,044 (40.4%) were gall wasps while 90,031 (59.6%) were other arthropods. We identified all arthropods to superfamily, family, or, where possible, to genus. We provide raw numbers and summaries of collections, alongside notes on natural history, ecology, and previously published associations for each taxon. For eight common gall-associated genera (Synergus, Ceroptres, Euceroptres, Ormyrus, Torymus, Eurytoma, Sycophila, and Euderus), we also connect rearing records to gall wasp phylogeny, geography, and ecology -including host tree and gall location (host organ), and their co-occurrence with other insect genera. Though the diversity of gall wasps and the large size of these communities is such that many Nearctic oak gall-associated insects still remain undescribed, this large collection and identification effort should facilitate the testing of new and varied ecological and evolutionary hypotheses in Nearctic oak galls.

The spectrum of Epstein-Barr virus infections of the central nervous system after organ transplantation.

BACKGROUND: Epstein-Barr virus (EBV)-related neurologic complications have a diverse presentation in transplant recipients, creating diagnostic and therapeutic challenges for clinicians. In this case series, we report unique manifestations of EBV related neurologic complications following solid organ transplant and highlight pitfalls in management. CASE PRESENTATIONS: A retrospective search of the electronic medical record of all patients from January 2015 to December 2020 who underwent solid organ transplantation and had central nervous system complications as determined by ICD-10 codes were included. Three patients with unique manifestation of EBV-related neurologic complications after liver transplantation were identified. The first was a 52-year-old man with a live-donor liver transplant 11 years prior for Budd-Chiari syndrome presented with several weeks of headache and several lesions on brain MRI; he was diagnosed with primary central nervous system post-transplant lymphoproliferative disorder. The second patient was a 63-year-old man with a deceased-donor liver transplant 16 years prior for alpha-1-antitrypsin deficiency and was found to have a stroke; he was diagnosed with EBV encephalitis. The final patient was a 75-year-old woman with a deceased-donor liver transplant six years prior for primary biliary cirrhosis who presented with four months of gait instability; she was diagnosed with EBV myelitis. A review of the literature was performed to supplement description of the different diseases. CONCLUSIONS: EBV-related central nervous infection in post-transplant patients can manifest in a variety of neurologic syndromes, which can be challenging to diagnose. Careful correlation of clinical, pathologic, and radiologic findings and a high index of suspicion are crucial in identification and appropriate management.